I've built a PXE install server which installs Ubuntu 15.04 using a Kickstart script and it's working fine on VMWare / Virtual Box VM's. 15 minute install at most.

I tried this on Dell R710's yesterday and the initial TFTP boot process isn't an issue and the installer runs and (only without the %posts) gives an install sucess message and reboots. The server then BIOS POST's then stuck on a black screen (VGA and DRAC). It appears to be getting an IP Address (DHCP) but no SSH (Kickstart script).